incubator-nuttx/arch/sparc/include/spinlock.h

85 lines
3.3 KiB
C

/****************************************************************************
* arch/sparc/include/spinlock.h
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
#ifndef __ARCH_SPARC_INCLUDE_SPINLOCK_H
#define __ARCH_SPARC_INCLUDE_SPINLOCK_H
/****************************************************************************
* Included Files
****************************************************************************/
#ifndef __ASSEMBLY__
# include <stdint.h>
#endif /* __ASSEMBLY__ */
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define SP_UNLOCKED 0 /* The Un-locked state */
#define SP_LOCKED 1 /* The Locked state */
/****************************************************************************
* Public Types
****************************************************************************/
#ifndef __ASSEMBLY__
/* The Type of a spinlock.
*
* This must be a uint32_ becaue it will be set using S32C1I instruction.
* That instruction atomically stores to a memory location only if its
* current value is the expected one. The state register (SCOMPARE1) is
* used to provide the additional comparison operand. Some implementations
* also have a state register (ATOMCTL) for further control of the atomic
* operation in cache and on the PIF bus.
*/
typedef uint32_t spinlock_t;
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
/****************************************************************************
* Name: up_testset
*
* Description:
* Perform an atomic test and set operation on the provided spinlock.
*
* This function must be provided via the architecture-specific logic.
*
* Input Parameters:
* lock - The address of spinlock object.
*
* Returned Value:
* The spinlock is always locked upon return. The value of previous value
* of the spinlock variable is returned, either SP_LOCKED if the spinlock
* as previously locked (meaning that the test-and-set operation failed to
* obtain the lock) or SP_UNLOCKED if the spinlock was previously unlocked
* (meaning that we successfully obtained the lock)
*
****************************************************************************/
/* See prototype in nuttx/include/nuttx/spinlock.h */
#endif /* __ASSEMBLY__ */
#endif /* __ARCH_SPARC_INCLUDE_SPINLOCK_H */